Cutting tool assembly

ABSTRACT

A cutting tool assembly includes a tool body and a tool holder including a longitudinal axis around which the tool holder is configured to spin. The tool holder includes a central portion connected to the tool body comprising a fastener hole perpendicular with the longitudinal axis and configured to receive a securing fastener, wherein the fastener hole is offset from the longitudinal axis. The tool holder further includes an eccentric drive member connected to the cylindrical portion. The tool holder can optionally further include an end alignment cylinder connected to the eccentric drive member.

CROSS-REFERENCE TO RELATED APPLICATIONS

This disclosure is a continuation in part of U.S. patent applicationSer. No. 15/485,945 filed on Apr. 12, 2017, which is hereby incorporatedby reference.

TECHNICAL FIELD

This disclosure is related to an apparatus useful to align and secure acutting tool assembly to a mating tool driver assembly. In particular,the disclosure is related to a configuration useful to secure thecutting tool assembly and easily release the tool at the completion of acutting task.

BACKGROUND

The statements in this section merely provide background informationrelated to the present disclosure. Accordingly, such statements are notintended to constitute an admission of prior art.

A cutting tool assembly is configured to receive an input torque from amating tool driver assembly. The cutting tool assembly includes at leastone cutting edge upon a tool tip that utilizes the input torque to cut aworkpiece.

U.S. Pat. No. 5,468,102 titled “Milling Tool Holder” for which thepresent applicant was the sole inventor discloses one previously knownmethod and apparatus for securing a cutting tool assembly to a matingtool driver and is included herein by reference. According to thisreference, a tool holder portion of a cutting tool assembly is providedwith a cylindrical section. A pair of conically shaped screw cavitiescan be formed in opposite sides of the cylindrical section, such thatwhen the cylindrical portion is inserted within a mating cylindricalcavity in a mating tool driver, a pair of threaded fasteners can be usedto lock the tool holder portion into place. This design has a number ofadvantages, however, it also includes a drawback that the screwstogether bear a large or majority portion of the input torque applied tothe tool through the mating tool driver. This input torque applied tothe fasteners can damage the fasteners, which can have a number ofadverse affects including making disassembly of the tool difficult orimpossible. Some tools must be destroyed when the fasteners deform toomuch after rough use.

U.S. Pat. No 8,360,699 titled “Cutting Tool Assembly with an EccentricDrive Member” for which the present applicant was the sole inventordiscloses one previously known method and apparatus for securing acutting tool assembly to a mating tool driver and is included herein byreference. According to this reference, a tool holder portion of acutting tool assembly is provided with a first conical portion attachedto a second eccentric or oval shaped drive member portion, with a thirdcylindrical portion including a locking mechanism. The eccentric drivemember provides a benefit, enabling the tool to be rotated within themating tool driver, with surfaces of the eccentric drive member aligningto a mating oval shaped cavity. In this way, the eccentric drive membercan transmit torque from the mating tool driver to the cutting toolassembly without deforming a plurality of set screws. This design has anumber of advantages, however, it also includes a drawback that theconical section and a mating conical cavity in the mating tool drivermust be constructed to tight tolerances in order to ensure proper toolalignment. Such tight tolerances slow manufacturing time of the cuttingtool assembly and introduce a source of tool malfunction, in that anysmall deformity or damage to the conical section can invalidate the toolor require intensive repair of the conical section to realign the tool.Further, because the conical section, by increasing in size toward theflat collar section joining the tool holder portion to the rest of thecutting tool assembly body, the size of that flat collar is reduced.This increases an ability of the tool to cant or tilt slightly withinthe cavity of the mating tool driver. Combined with tool strain createdwhile cutting through a work piece, this tilt can lock the cutting toolassembly within the mating tool driver. As a result, in order to removethe cutting tool assembly from the mating tool driver, one mustfrequently use a hammer to knock the cutting tool assembly loose fromthe mating tool driver, frequently causing damage or increased wear tothe cutting tool assembly.

SUMMARY

A cutting tool assembly includes a tool body and a tool holder includinga longitudinal axis around which the tool holder is configured to spin.The tool holder includes a central portion connected to the tool bodycomprising a fastener hole perpendicular with the longitudinal axis andconfigured to receive a securing fastener, wherein the fastener hole isoffset from the longitudinal axis. The tool holder further includes aneccentric drive member connected to the cylindrical portion. The toolholder can optionally further include an end alignment cylinderconnected to the eccentric drive member.

BRIEF DESCRIPTION OF THE DRAWINGS

One or more embodiments will now be described, by way of example, withreference to the accompanying drawings, in which:

FIG. 1 illustrates an exemplary cutting tool assembly including a toolholder and a cutting tool body, including a cylindrical portion, atrigon portion, and a fastener hole, in accordance with the presentdisclosure;

FIG. 2 illustrates the cutting tool assembly of FIG. 1 in side view, inaccordance with the present disclosure;

FIG. 3 illustrates the cutting tool assembly of FIG. 1, viewed from thebottom, in accordance with the present disclosure;

FIG. 4 illustrates the cutting tool assembly of FIG. 1 in perspectiveview, in accordance with the present disclosure;

FIG. 5 illustrates the cutting tool assembly of FIG. 1 inserted withinan exemplary mating tool driver assembly in cross-section, in accordancewith the present disclosure;

FIG. 6 illustrates the trigon portion of FIG. 5 within a trigon shapedcavity of mating tool driver, in cross section, in accordance with thepresent disclosure;

FIGS. 7A and 7B illustrate an exemplary tool holder configuration of aknown prior art tool holder, including a conical section used to alignthe tool holder to a mating cavity, in accordance with the presentdisclosure;

FIG. 7A illustrates the tool holder and mating cavity in an initialunstressed condition;

FIG. 7B illustrates the tool holder and mating cavity of FIG. 7A in astressed state, with a torque and a lateral force applied thereto;

FIGS. 8A and 8B illustrate an exemplary tool holder configurationaccording to the present application, in accordance with the presentdisclosure;

FIG. 8A illustrates the exemplary tool holder of the cutting toolassembly in an initial unstressed state;

FIG. 8B illustrates the cutting tool assembly of FIG. 8A in a stressedstate, with a torque and a lateral force applied thereto;

FIG. 9 illustrates an alternative embodiment of an exemplary cuttingtool assembly including a tool holder including an end alignmentcylinder and a fastener hole which is offset from a center of theassembly, in accordance with the present disclosure;

FIG. 10 illustrates the cutting tool assembly of FIG. 9 in sectionalview, in accordance with the present disclosure;

FIG. 11 illustrates an alternative embodiment of the cutting toolassembly of FIG. 9, with slightly angled walls, in accordance with thepresent disclosure;

FIG. 12 illustrates the cutting tool assembly of FIG. 11 in sectionalview, illustrating a first and a second fastener hole, each configuredfor a different tool spinning direction, in accordance with the presentdisclosure;

FIG. 13 illustrates an alternative exemplary cutting tool assembly insectional view, with a fastener hole configured for a tool that rotatesin an opposite direction from the cutting tool assembly of FIGS. 9 and10, in accordance with the present disclosure; and

FIG. 14 illustrates an exemplary alternative embodiment to the cuttingtool assembly of FIG. 12, illustrating alternative embodiments of thefirst and second fastener holes, in accordance with the presentdisclosure.

DETAILED DESCRIPTION

A tool holder portion of a cutting tool assembly includes a cylindricalalignment portion and an eccentric drive member portion. The cylindricalalignment portion can include a fastener cavity configured to accept athreaded fastener in order to secure the tool holder within a matingcavity. The eccentric drive member portion is configured to be alignedwith a mating eccentric cavity within a mating tool driver, such that aportion of input torque transmitted from the mating tool driver to thecutting tool assembly is transmitted through the eccentric drive member,with the fastener transmitting one of a portion of the input torque ornone of the input torque.

Referring now to the drawings, wherein the showings are for the purposeof illustrating certain exemplary embodiments only and not for thepurpose of limiting the same, FIG. 1 illustrates an exemplary cuttingtool assembly 10 including tool holder 12 and cutting tool body 20. Toolholder 12 includes cylindrical portion 30 and trigon portion 40. Toolholder 12 is configured to be inserted within a tool driver assembly,which provides input torque to the cutting tool assembly 10. Tool holder12 is configured to removably affix the cutting tool assembly 10 to thetool driver assembly, providing a precisely controllable cutting tooledge or edges while enabling easy removal of the cutting tool assembly10 from the tool driver assembly after a cutting task is complete.

Cylindrical portion 30 includes substantially parallel side walls 36.Fastener hole 32 permits a fastener to be used to lock the tool holder12 into place within the tool driver assembly. Cutting tool body 20includes a wider radius than cylindrical portion 30. Cylindrical portion30 is attached to flat bottom face 22 of cutting tool body 20.Cylindrical portion 30 serves as a first contact point with the matingtool driver assembly, locating the cutting tool assembly through precisefitting of the cylinder shape to a mating cylinder cavity and fixingthat spatial relationship with a fastener affixed though the tool driverassembly to fastener hole 32. The cylinder shape further prevents thecutting tool assembly 10 from canting or tilting within the tool driverassembly cavity, thereby preventing a tool lock condition.

Trigon portion 40 includes a eccentric drive member including asubstantially curved triangular cross-section defined by three flatterarcuate faces 44 separated by three rounded vertices 46. Trigon portion40 is attached to bottom flat face 34 of cylindrical potion 30 andincludes a flat bottom face 42. Trigon portion 40 is configured beinserted into a similar shaped trigon cavity within the mating tooldriver assembly, wherein the cavity within the mating tool driverassembly is slightly larger than trigon portion 40. Trigon portion 40,once within the mating cavity, is slightly rotated in an oppositedirection which torque is applied through the tool, such that three ofthe faces 44 are abutted and in contact with mating faces of the matingcavity. The faces 44 of the trigon portion 40, in contact with themating cavity, serve as a second contact point with the mating tooldriver assembly. The triangular cross section of trigon portion 40,portion in other embodiments, can be substituted with a eccentric drivemember with a similar oval or rounded square.

FIG. 2 illustrates the cutting tool assembly 10 of FIG. 1 in side view.Cutting tool assembly 10 includes cutting tool body 20 and tool holder12 including cylindrical portion 30 and trigon portion 40. Fastener hole32 is illustrated in profile.

FIG. 3 illustrates the cutting tool assembly 10 of FIG. 1, viewed fromthe bottom. Cutting tool assembly 10 includes cutting tool body 20.Further, cylindrical portion 30 is illustrated including fastener hole32. Further, trigon portion 40 is illustrated including a substantiallycurved triangular cross-section defined by three flatter arcuate faces44 separated by three rounded vertices 46.

FIG. 4 illustrates the cutting tool assembly 10 of FIG. 1 in perspectiveview. Cutting tool assembly 10 includes cutting tool body 20 includingflat bottom face 22, cylindrical portion 30 including flat bottom face32, and trigon portion 40 including flat bottom face 42. Fastener hole32 is illustrated.

FIG. 5 illustrates the cutting tool assembly 10 of FIG. 1 insertedwithin an exemplary mating tool driver assembly 100 in cross-section.Cutting tool assembly 10 includes cutting tool body 20 including flatbottom face 22, cylindrical portion 30, and trigon portion 40. Tooldriver assembly 100 includes flat face 130 mating to bottom flat face22, cylindrical shaped cavity 110 mating to walls 36 of cylindricalportion 30, and trigon shaped cavity 120 mating to trigon portion 40.Fastener 150 is illustrated inserted within cavity 140 of tool driverassembly 150 affixed within fastener hole 32. Section 160 is providedfor illustration in related FIG. 6.

FIG. 5 illustrates cylindrical portion 30 and bottom flat face 22.Parallel side walls 36 of cylindrical portion 30 are substantiallyperpendicular to bottom flat face 22. Whereas the configuration of U.S.Pat. No. 8,360,699 includes a conical section, where side walls of thatsection engage with mating cavity walls based upon how far the toolholder is inserted into the cavity. Alignment of the side walls to thatprevious design are dependent upon full engagement of the tool holder,and if in the straining and related deformation of the tool as torque istransmitted through the tool the walls are no longer fully engaged,alignment of the tool can be compromised. The present configuration issuperior to that previous configuration because cylindrical portion 30,with walls parallel to a longitudinal axis of the tool holder, alignswith the mating cylindrical shaped cavity 110 regardless of strain anddeformation of cylindrical portion 30. Unlike a conical section,alignment of cylindrical portion 30 to the mating cavity is notdependent upon the portion being firmly seated with the mating cavity inan axial direction.

FIGS. 7A and 7B illustrate an exemplary tool holder configuration of aknown prior art tool holder, including a conical section used to alignthe tool holder to a mating cavity. FIG. 7A illustrates the tool holderand mating cavity in an initial unstressed condition. Cutting toolassembly 200 is illustrated including conical portion 210, eccentricdriver portion 220, and retention portion 222. Conical portion 210includes side walls 212 which are angled in relation to a longitudinalaxis of the tool. Bottom flat face 202 connects conical portion 210 witha body of the tool assembly. Retention portion 222 locks into matingfeatures in mating tool driver 205. In the relaxed state of FIG. 7A,side walls 212 align with walls of the mating cavity in mating tooldriver 205.

FIG. 7B illustrates the tool holder and mating cavity of FIG. 7A in astressed state, with a torque 240 and a lateral force 242 appliedthereto. As stress is applied to cutting tool assembly 200, the toolassembly deforms. In the exemplary illustration of FIG. 7B, gap 214 isillustrated between conical portion 210 and the neighboring cavity wall.This visible gap is provided for purposes of illustration, whereasdeformation in actual parts under stress can be significant althoughless visible to an ordinary observer. With the creation of gap 214, theoriginal alignment of the tool holder of cutting tool assembly 200 andthe mating tool driver can be disturbed, with the deformed piecesreturning to a different alignment than the original alignment. This cancreate a tool lock condition, where some of the deformation in thepieces remains and locks the pieces together, requiring a mitigating actsuch as a hammer strike to separate the tool pieces.

FIGS. 8A and 8B illustrate an exemplary tool holder configurationaccording to the present application. FIG. 8A illustrates the exemplarytool holder of the cutting tool assembly in an initial unstressed state.Cutting tool assembly 10 is illustrated including cylindrical portion 30and trigon portion 40, with bottom flat surface 22 joining cylindricalportion 30 to a main body of cutting tool assembly 10. Cutting tool 10is illustrated within a mating tool driver 250.

FIG. 8B illustrates cutting tool assembly 10 of FIG. 8A in a stressedstate, with a torque 240 and a lateral force 242 applied thereto. Asstress is applied to cutting tool assembly 10, the tool assemblydeforms. However, alignment of the tool holder within the cavity ofmating tool driver 250 is dependent upon parallel side walls 36 ofcylindrical portion 30 aligning with the parallel side walls of themating cylindrical shape cavity of mating tool driver 250. Gap 230caused by deformation of cutting tool assembly 10 typically createsspace between parallel walls 36 and the mating cavity walls. Uponremoving stress from the pieces, the cylindrical walls tend to relax totheir original alignment or include less residual stress than the piecesof FIG. 7B. Further, bottom flat face 22, including a larger surfacearea than a comparable bottom flat face 202 of FIG. 7A due to thewidening radius of the conical portion, tends to keep the cutting toolassembly 10 in alignment with the mating surface of mating tool driver250. As a result, cutting tool assembly 10 of FIG. 8B exhibits easierdecoupling and less opportunity to damage the tools than the cuttingtool assembly of FIG. 7B.

FIG. 6 illustrates the trigon portion 40 of FIG. 5 within trigon shapedcavity 120 of tool driver assembly 100, in cross section as defined bysection 160 of FIG. 5. Trigon portion 40 includes a substantially curvedtriangular cross-section defined by three flatter arcuate faces 44separated by three rounded vertices 46. As the trigon portion 40 isrotated within cavity 120, faces 44 come into contact with mating wallsof cavity 120.

The cutting tool assembly of the present disclosure can include anynumber of known cutting instruments or tooling, included but not limitedto an endmill, a ballmill, a drill, an indexable cutter, a modularcutter, and a chuck for attaching various bits.

FIG. 9 illustrates an alternative embodiment of an exemplary cuttingtool assembly 310 including tool holder 312 and cutting tool body 320.Tool holder 312 includes a central portion including a cylindricalportion 330, trigon portion 340, and an end alignment cylinder 350. Toolholder 312 is configured to be inserted within a tool driver assembly,which provides input torque to the cutting tool assembly 310. Toolholder 312 is configured to removably affix the cutting tool assembly310 to the tool driver assembly, providing a precisely controllablecutting tool edge or edges while enabling easy removal of the cuttingtool assembly 310 from the tool driver assembly after a cutting task iscomplete. Longitudinal axis 355 is illustrated through a center ofcutting tool assembly 310 about which the assembly is configured tospin.

The central portion can include different shapes such as cylindricalportion 330 which can include substantially parallel side walls.Fastener hole 332 permits a fastener to be used to lock the tool holder312 into place within the tool driver assembly. Cutting tool body 320includes a wider radius than cylindrical portion 330. Cylindricalportion 330 is attached to flat bottom face 322 of cutting tool body320. Cylindrical portion 330 serves as a first contact point with themating tool driver assembly, locating the cutting tool assembly throughprecise fitting of the cylinder shape to a mating cylinder cavity andfixing that spatial relationship with a fastener affixed though the tooldriver assembly to fastener hole 332. The cylinder shape furtherprevents the cutting tool assembly 310 from canting or tilting withinthe tool driver assembly cavity, thereby preventing a tool lockcondition.

Trigon portion 340 includes an eccentric drive member including asubstantially curved triangular cross-section defined by three flatterarcuate faces separated by three rounded vertices. Trigon portion 340 isattached to bottom flat face 334 of cylindrical potion 330 and includesa flat bottom face 342. Trigon portion 340 is configured be insertedinto a similar shaped trigon cavity within the mating tool driverassembly, wherein the cavity within the mating tool driver assembly isslightly larger than trigon portion 340. The triangular cross section oftrigon portion 340, portion in other embodiments, can be substitutedwith a eccentric drive member with a similar oval or rounded square.

End alignment cylinder 350 is attached to flat bottom face 342 andfurther provides to align the tool holder 312 within the mating cavityand stop assembly 310 from canting while in use.

FIG. 10 illustrates the cutting tool assembly 310 of FIG. 9 in sectionalview. Cylindrical portion 330 is illustrated in cross section through apoint at a center of fastener hole 332. Fastener hole 332 is illustratedin profile and includes a cone shaped lead in. Fastener hole 332 isperpendicular to longitudinal axis 355, being formed at a 90 degreeangle into cylindrical portion 330 as compared to longitudinal axis 355.However, fastener hole 332 is offset to one side longitudinal axis 355,such that a centerline of fastener hole 332 is not in line with axis355. As cutting tool assembly 310 is set within a mating cavity, afastener being driven into fastener hole 332 acts to rotate cutting toolassembly slightly in the illustrated counter clockwise direction. Thisrotation sets the trigon portion of cutting tool assembly 310 firmlyagainst the mating cavity to the trigon portion. This forced rotationfurther aligns assembly 310 within the mating cavity and reduces play inthe part, such that use of assembly 310 to cut a work piece is lesslikely to result in assembly 310 being locked within the mating cavity.

FIG. 11 illustrates an alternative embodiment of the cutting toolassembly of FIG. 9, with slightly angled walls. Cutting tool assembly410 includes tool holder 412 and cutting tool body 420. Tool holder 412includes central portion 430, trigon portion 440, and an end alignmentcylinder 450. Central portion 430 includes slightly angled walls andfastener hole 432. Fastener hole 432 is perpendicular to longitudinalaxis 455, being formed at a 90 degree angle into central portion 430 ascompared to longitudinal axis 455. However, fastener hole 432 is offsetto one side longitudinal axis 455, such that a centerline of fastenerhole 432 is not in line with axis 455.

FIG. 12 illustrates the cutting tool assembly of FIG. 11 in sectionalview, illustrating a first and a second fastener hole, each configuredfor a different tool spinning direction. Central portion 430 isillustrated in cross section through a point at a center of firstfastener hole 432 and a center of second fastener hole 433. Fastenerholes 432 and 433 are illustrated at a same longitudinal location oncentral portion 430. In other embodiments, fastener holes 432 and 433can be at different longitudinal locations on the central portion.Fastener holes 432 and 433 are illustrated in profile and include coneshaped lead ins. Fastener holes 432 and 433 are each perpendicular tolongitudinal axis 455, being formed at a 90 degree angle into centralportion 430 as compared to longitudinal axis 455. However, fastenerholes 432 and 433 are each offset to one side longitudinal axis 455. Ascutting tool assembly 410 is set within a mating cavity, a fastenerbeing driven into one of fastener holes 432 and 433 acts to rotatecutting tool assembly slightly in the direction of spinning.

Depending upon a tool spinning direction, either fastener hole 432 or433 can be used. In one embodiment, either fastener hole 432 or fastenerhole 433 can individually be formed in cutting tool assembly 410 inisolation of the other fastener hole. FIG. 13 illustrates an alternativeexemplary cutting tool assembly in sectional view, with a fastener holeconfigured for a tool that rotates in an opposite direction from thecutting tool assembly of FIGS. 9 and 10. Central portion 530 isillustrated in cross section through a point at a center of fastenerhole 533. Fastener hole 533 is illustrated in profile and includes acone shaped lead in. Fastener hole 533 is perpendicular to longitudinalaxis 555, being formed at a 90 degree angle into central portion 530 ascompared to longitudinal axis 555.

FIG. 14 illustrates an exemplary alternative embodiment to the cuttingtool assembly of FIG. 12, illustrating alternative embodiments of thefirst and second fastener holes. Central portion 630 is illustrated incross section through a point at a center of first fastener hole 632 anda center of second fastener hole 633. Fastener holes 632 and 633 areillustrated at a same longitudinal location on central portion 630. Inother embodiments, fastener holes 632 and 633 can be at differentlongitudinal locations on the central portion. Fastener holes 632 and633 are illustrated in profile. Fastener hole 632 includes a roundedend. Fastener hole 633 includes a squared end. Fastener holes 632 and633 can each be perpendicular to longitudinal axis 655, being formed ata 90 degree angle into central portion 630 as compared to longitudinalaxis 655.

The disclosure has described certain preferred embodiments andmodifications of those embodiments. Further modifications andalterations may occur to others upon reading and understanding thespecification. Therefore, it is intended that the disclosure not belimited to the particular embodiment(s) disclosed as the best modecontemplated for carrying out this disclosure, but that the disclosurewill include all embodiments falling within the scope of the appendedclaims.

1. An apparatus comprising a cutting tool assembly, comprising: a toolbody; and a tool holder comprising a longitudinal axis around which thetool holder is configured to spin, the tool holder comprising: a centralportion connected to the tool body comprising a fastener holeperpendicular with the longitudinal axis and configured to receive asecuring fastener, wherein the fastener hole is offset from thelongitudinal axis; and an eccentric drive member connected to thecentral portion.
 2. The apparatus of claim 1, the tool holder furthercomprising an end alignment cylinder connected to the eccentric drivemember.
 3. The apparatus of claim 2, wherein the central portioncomprises a cylindrical portion with side walls parallel to thelongitudinal axis.
 4. The apparatus of claim 2, wherein the fastenerhole comprises a first fastener hole; and wherein the central portionfurther comprises a second fastener hole offset from the longitudinalaxis.
 5. The apparatus of claim 4, wherein the first fastener hole andthe second fastener hole are at a same longitudinal position on thecentral portion.
 6. The apparatus of claim 1, wherein the centralportion comprises a cylindrical portion with side walls parallel to thelongitudinal axis.
 7. The apparatus of claim 6, wherein the fastenerhole comprises a first fastener hole; and wherein the central portionfurther comprises a second fastener hole offset from the longitudinalaxis.
 8. The apparatus of claim 7, wherein the first fastener hole andthe second fastener hole are at a same longitudinal position on thecentral portion.
 9. The apparatus of claim 1, wherein the fastener holecomprises a first fastener hole; and wherein the central portion furthercomprises a second fastener hole offset from the longitudinal axis. 10.The apparatus of claim 9, wherein the first fastener hole and the secondfastener hole are at a same longitudinal position on the centralportion.
 11. The apparatus of claim 1, wherein the central portioncomprises angled side walls.
 12. The apparatus of claim 11, the toolholder further comprising an end alignment cylinder connected to theeccentric drive member.
 13. The apparatus of claim 1, wherein thefastener hole comprises a cone-shaped fastener hole.
 14. An apparatuscomprising a cutting tool assembly, comprising: a tool body; and a toolholder comprising a longitudinal axis around which the tool holder isconfigured to spin, the tool holder comprising: a central portionconnected to the tool body comprising a cone-shaped fastener holeperpendicular with the longitudinal axis and configured to receive asecuring fastener, wherein the cone-shaped fastener hole is offset fromthe longitudinal axis; an eccentric drive member connected to thecentral portion; and an end alignment cylinder connected to an end ofthe eccentric drive member.
 15. The apparatus of claim 14, wherein thecentral portion comprises a cylindrical portion with side walls parallelto the longitudinal axis; wherein the fastener hole comprises a firstfastener hole; and wherein the central portion further comprises asecond fastener hole offset from the longitudinal axis at a samelongitudinal position on the central portion as the first fastener hole.